Commit 1e736f14 authored by Alex Mastro's avatar Alex Mastro Committed by Alex Williamson
Browse files

vfio/pci: print vfio-device syspath to fdinfo 



Print the PCI device syspath to a vfio device's fdinfo. This enables tools
to query which device is associated with a given vfio device fd.

This results in output like below:

$ cat /proc/"$SOME_PID"/fdinfo/"$VFIO_FD" | grep vfio
vfio-device-syspath: /sys/devices/pci0000:e0/0000:e0:01.1/0000:e1:00.0/0000:e2:05.0/0000:e8:00.0

Signed-off-by: default avatarAlex Mastro <amastro@fb.com>
Reviewed-by: default avatarAmit Machhiwal <amachhiw@linux.ibm.com>
Tested-by: default avatarAmit Machhiwal <amachhiw@linux.ibm.com>
Link: https://lore.kernel.org/r/20250804-show-fdinfo-v4-1-96b14c5691b3@fb.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 1b237f19

Documentation/filesystems/proc.rst

+14 −0
Original line number Diff line number Diff line
@@ -2166,6 +2166,20 @@ DMA Buffer files 
where 'size' is the size of the DMA buffer in bytes. 'count' is the file count of

the DMA buffer file. 'exp_name' is the name of the DMA buffer exporter.



VFIO Device files

~~~~~~~~~~~~~~~~



::



	pos:    0

	flags:  02000002

	mnt_id: 17

	ino:    5122

	vfio-device-syspath: /sys/devices/pci0000:e0/0000:e0:01.1/0000:e1:00.0/0000:e2:05.0/0000:e8:00.0



where 'vfio-device-syspath' is the sysfs path corresponding to the VFIO device

file.



3.9	/proc/<pid>/map_files - Information about memory mapped files

---------------------------------------------------------------------

This directory contains symbolic links which represent memory mapped files

drivers/vfio/vfio_main.c

+20 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/pseudo_fs.h>

#include <linux/rwsem.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/slab.h>

#include <linux/stat.h>

#include <linux/string.h>
@@ -1355,6 +1356,22 @@ static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma) 
	return device->ops->mmap(device, vma);

}



#ifdef CONFIG_PROC_FS

static void vfio_device_show_fdinfo(struct seq_file *m, struct file *filep)

{

	char *path;

	struct vfio_device_file *df = filep->private_data;

	struct vfio_device *device = df->device;



	path = kobject_get_path(&device->dev->kobj, GFP_KERNEL);

	if (!path)

		return;



	seq_printf(m, "vfio-device-syspath: /sys%s\n", path);

	kfree(path);

}

#endif



const struct file_operations vfio_device_fops = {

	.owner		= THIS_MODULE,

	.open		= vfio_device_fops_cdev_open,
@@ -1364,6 +1381,9 @@ const struct file_operations vfio_device_fops = { 
	.unlocked_ioctl	= vfio_device_fops_unl_ioctl,

	.compat_ioctl	= compat_ptr_ioctl,

	.mmap		= vfio_device_fops_mmap,

#ifdef CONFIG_PROC_FS

	.show_fdinfo	= vfio_device_show_fdinfo,

#endif

};



static struct vfio_device *vfio_device_from_file(struct file *file)